U.S. patent application number 12/992483 was filed with the patent office on 2011-05-26 for carbon nanotube composite, organic semiconductor composite, and field-effect transistor.
Invention is credited to Yukari Jo, Daisuke Kitazawa, Seiichiro Murase, Jun Tsukamoto.
Application Number | 20110121273 12/992483 |
Document ID | / |
Family ID | 41318709 |
Filed Date | 2011-05-26 |
United States Patent
Application |
20110121273 |
Kind Code |
A1 |
Jo; Yukari ; et al. |
May 26, 2011 |
CARBON NANOTUBE COMPOSITE, ORGANIC SEMICONDUCTOR COMPOSITE, AND
FIELD-EFFECT TRANSISTOR
Abstract
A carbon nanotube composite in which a conjugated polymer
containing repeating units containing a fused heteroaryl unit
having a nitrogen-containing double bond in the ring, and a
thiophene unit is attached to at least a part of the surface of a
carbon nanotube. The present invention reduces the hysteresis of a
field-effect transistor having a semiconductor layer containing a
carbon nanotube.
Inventors: |
Jo; Yukari; (Shiga, JP)
; Murase; Seiichiro; (Shiga, JP) ; Kitazawa;
Daisuke; (Shiga, JP) ; Tsukamoto; Jun; (Shiga,
JP) |
Family ID: |
41318709 |
Appl. No.: |
12/992483 |
Filed: |
November 5, 2009 |
PCT Filed: |
November 5, 2009 |
PCT NO: |
PCT/JP2009/058734 |
371 Date: |
January 28, 2011 |
Current U.S.
Class: |
257/40 ;
257/E51.006; 528/380; 977/742; 977/938 |
Current CPC
Class: |
H01L 51/0035 20130101;
H01L 51/0036 20130101; C01B 32/174 20170801; H01L 51/0545 20130101;
B82Y 40/00 20130101; H01L 51/0072 20130101; H01L 51/0566 20130101;
B82Y 10/00 20130101; H01L 51/0048 20130101; H01L 51/0004 20130101;
B82Y 30/00 20130101; H01L 51/10 20130101 |
Class at
Publication: |
257/40 ; 528/380;
257/E51.006; 977/938; 977/742 |
International
Class: |
H01L 51/10 20060101
H01L051/10; C08G 75/32 20060101 C08G075/32 |
Foreign Application Data
Date |
Code |
Application Number |
May 12, 2008 |
JP |
2008-124293 |
Jan 7, 2009 |
JP |
2009-001389 |
Claims
1. A carbon nanotube composite comprising a carbon nanotube and a
conjugated polymer comprising repeating units containing a fused
heteroaryl unit having a nitrogen-containing double bond in the
ring and a thiophene unit, wherein the conjugated polymer is
attached to at least a part of a surface of the carbon
nanotube.
2. The carbon nanotube composite according to claim 1, wherein the
fused heteroaryl unit having a nitrogen-containing double bond in
the ring is comprises a quinoxaline unit or a benzothiadiazole
unit.
3. The carbon nanotube composite according to claim 2, wherein the
conjugated polymer has a structure represented by the general
formula (1): ##STR00026## wherein R1 to R6 may be the same or
different, and each represent hydrogen, an alkyl group, a
cycloalkyl group, a heterocyclic group, an alkenyl group, a
cycloalkenyl group, an alkynyl group, an alkoxy group, an alkylthio
group, an arylether group, an arylthioether group, an aryl group, a
heteroaryl group, a halogen atom, a cyano group, a formyl group, a
carbamoyl group, an amino group, an alkylcarbonyl group, an
arylcarbonyl group, a carboxyl group, an alkoxycarbonyl group, an
aryloxycarbonyl group, an alkylcarbonyloxy group, an
arylcarbonyloxy group, or a silyl group, adjacent groups of R1 to
R6 may form a ring structure, A is selected from a single bond, an
arylene group, a heteroarylene group except for a thienylene group,
an ethenylene group and an ethynylene group, l and m represent an
integer of 0 to 10, and l+m.gtoreq.1, n represents a range of 2 to
1000, when l, m and n are 2 or more, each R1 to R6 and A may be the
same or different.
4. An organic semiconductor composite containing the carbon
nanotube composite as defined in claim 1, and an organic
semiconductor.
5. A field-effect transistor having a gate electrode, a gate
insulating layer, a semiconductor layer, a source electrode and a
drain electrode, wherein the semiconductor layer contains the
carbon nanotube composite as defined in claim 1.
6. The field-effect transistor according to claim 5, wherein the
semiconductor layer further contains an organic semiconductor.
7. The field-effect transistor according to claim 5, wherein the
transistor has a second insulating layer formed on an opposite side
of the gate insulating layer relative to the semiconductor
layer.
8. The field-effective transistor according to claim 7, wherein the
second insulating layer comprises a layer formed by a coating
method.
9. The field-effective transistor according to claim 7, wherein the
second insulating layer contains an organic polymer material
selected from the group consisting of polyfluoroethylene,
polynorbornene, polysiloxane, polyimide, polystyrene, polycarbonate
and a derivative thereof, a polyacrylic acid derivative, a
polymethacrylic acid derivative, and a copolymer containing
them.
10. The field-effective transistor according to claim 5, wherein at
least one layer of the gate insulating layer, the semiconductor
layer, and the second insulating layer contains an amine compound.
Description
TECHNICAL FIELD
[0001] The present invention relates to a carbon nanotube composite
in which a conjugated polymer is attached to at least a part of the
surface of a carbon nanotube, an organic semiconductor composite
containing the carbon nanotube composite and an organic
semiconductor, and a field-effect transistor.
BACKGROUND ART
[0002] In recent years, a field-effect transistor (hereinafter
referred to as FET) using an organic semiconductor excellent in
moldability as a semiconductor layer has been proposed. Since by
utilizing an organic semiconductor as an ink, it becomes possible
to form a circuit pattern directly on a substrate, by inkjet
technique or screening technique, FET using the organic
semiconductor is being studied actively in place of the
conventional inorganic semiconductor.
[0003] As an important index showing performance of FET, mobility
is exemplified. Improvement in mobility means improvement in
switching property of FET. For example, in a liquid crystal display
apparatus, it leads to realization of high gradation. In the case
of the liquid crystal display apparatus, mobility of FET is
required to be 0.1 cm.sup.2/Vsec or more.
[0004] In addition, as another important index, there is
hysteresis. Hysteresis expresses a variation wide of a current
value relative to voltage history, and it is necessary to make a
value of hysteresis small for stably driving FET.
[0005] As a technique for improving mobility, a method of using a
polymer composite having a carbon nanotube composite, in which a
conjugated polymer is attached to a part of the surface of a carbon
nanotube (e.g. see Patent Literatures 1 to 3), is disclosed.
However, when a semiconductor layer formed of the polymer composite
containing a carbon nanotube composite is used, although mobility
is improved, there was a problem that hysteresis is great.
PRIOR ART LITERATURE
Patent Literature
[0006] Patent Literature 1: JP-A No. 2006-265534 gazette (claims)
[0007] Patent Literature 2: JP-A No. 2003-96313 gazette (claims)
[0008] Patent Literature 3: JP-A No. 2005-89735 gazette
(claims)
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0009] An object of the present invention is to reduce the
hysteresis of a field-effect transistor having a semiconductor
layer containing a carbon nanotube.
Means for Solving the Problems
[0010] The present invention is a carbon nanotube composite in
which a conjugated polymer comprising repeating units containing a
fused heteroaryl unit having a nitrogen-containing double bond in
the ring and a thiophene unit is attached to at least a part of the
surface of a carbon nanotube.
[0011] In addition, the present invention is a field-effect
transistor having a gate electrode, a gate insulating layer, a
semiconductor layer, a source electrode and a drain electrode,
wherein the semiconductor layer contains the carbon nanotube
composite.
Effects of the Invention
[0012] According to the present invention, a field-effect
transistor exhibiting high mobility and having reduced hysteresis
can be provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic cross-sectional view showing FET which
is one aspect of the present invention.
[0014] FIG. 2 is a schematic cross-sectional view showing FET which
is another aspect of the present invention.
MODES FOR CARRYING OUT THE INVENTION
[0015] First, the carbon nanotube composite of the present
invention will be described in detail. The carbon nanotube
(hereinafter, referred to as CNT) composite of the present
invention is a CNT composite in which a conjugated polymer
comprising repeating units containing a fused heteroaryl unit
having a nitrogen-containing double bond in the ring and a
thiophene unit is attached to at least a part of the surface. In
FET, while inclusion of CNT in a semiconductor layer can improve
mobility, there was a problem that hysteresis is increased. As one
cause for increase in hysteresis, it is thought that a trap amount
due to impurities in CNT is changed depending on gate voltage
history. In the present invention, hysteresis could be considerably
improved while high mobility is retained, by using a CNT composite
in which a conjugated polymer comprising repeating units containing
a fused heteroaryl unit having a nitrogen-containing double bond in
the ring and a thiophene unit is attached to at least a part of the
surface of CNT. This is presumed that the trap can be decreased by
a fused heteroaryl unit having a nitrogen-containing double bond in
the ring, which is an electron withdrawing group. In addition, by a
conjugated polymer having a thiophene unit, adherability between
CNT and the conjugated polymer is increased, and CNT can be
dispersed in a semiconductor layer well.
[0016] In the present invention, the state where the conjugated
polymer is attached to at least a part of the surface of CNT means
the state where a part or all of the surface of CNT is covered with
the conjugated polymer. It is presumed that CNT can be covered with
the conjugated polymer because interaction is generated by
overlapping of n electron clouds derived from both conjugated
structures. Whether CNT is covered with the conjugated polymer or
not can be determined by a fact that the reflected color of covered
CNT approaches the color of the conjugated polymer from the color
of not covered CNT. Quantitatively, the presence of an attached
substance, and a weight ratio of the attached substance relative to
CNT can be identified by elementary analysis such as X-ray
photoelectron spectrometry (XPS).
[0017] Examples of a method of attaching the conjugated polymer to
CNT include (I) a method of adding CNT to a melted conjugated
polymer, and mixing them, (II) a method of dissolving the
conjugated polymer in a solvent, adding CNT thereto, and mixing
them, (III) a method of pre-dispersing CNT in a solvent with
ultrasound etc., and adding the conjugated polymer thereto, and
mixing them, and (IV) a method of placing the conjugated polymer
and CNT in a solvent, irradiating this mixed system with
ultrasound, and mixing them. In the present invention, any method
may be used, or a plurality of methods may be combined.
[0018] The conjugated polymer comprising repeating units containing
a fused heteroaryl unit having a nitrogen-containing double bond in
the ring, and a thiophene unit (hereinafter, referred to as
conjugated polymer) may contain another unit in the repeating unit
as far as it comprises these both units in the repeating unit. In
addition, from a viewpoint of easy attachment to CNT, it is
preferable that a weight average molecule weight is 1000 or more.
Herein, the conjugated polymer refers to a compound in which a
repeating unit has a conjugated structure, and a polymerization
degree is 2 or more.
[0019] Examples of the fused heteroaryl unit having a
nitrogen-containing double bond in the ring include units of
thienopyrrole, pyrrolothiazole, pyrrolopyridazine, benzimidazole,
benzotriazole, benzoxazole, benzothiazole, benzothiadiazole,
quinoline, quinoxaline, benzotriazine, thienooxazole,
thienopyridine, thienothiazine, and thienopyrazine. Among them,
particularly, a benzothiadiazole unit or a quinoxaline unit is
preferable. By having these units, trap derived from CNT can be
more effectively decreased.
[0020] As the conjugated polymer, a conjugated polymer having the
following structure is particularly preferable.
##STR00001##
[0021] Wherein, R.sup.1 to R.sup.6 may be the same or different,
and each represent hydrogen, an alkyl group, a cycloalkyl group, a
heterocyclic group, an alkenyl group, a cycloalkenyl group, an
alkynyl group, an alkoxy group, an alkylthio group, an arylether
group, an arylthioether group, an aryl group, a heteroaryl group, a
halogen atom, a cyano group, a formyl group, a carbamoyl group, an
amino group, an alkylcarbonyl group, an arylcarbonyl group, a
carboxyl group, an alkoxycarbonyl group, an aryloxycarbonyl group,
an alkylcarbonyloxy group, an arylcarbonyloxy group or a silyl
group. Alternatively, adjacent groups of R.sup.1 to R.sup.6 may
form a ring structure. A is selected from a single bond, an arylene
group, heteroarylene group except for a thienylene group, an
ethenylene group, and an ethynylene group. l and m each represent
an integer of 0 to 10, and n represents a range of 2 to 1000. When
l, m and n are 2 or more, R.sup.1 to R.sup.6 and A may be the same
or different in each repeating unit.
[0022] The alkyl group represents a saturated aliphatic hydrocarbon
group, such as a methyl group, an ethyl group, an n-propyl group,
an isopropyl group, a n-butyl group, a sec-butyl group, and a
tert-butyl group, and may or may not have a substituent. When the
alkyl group has a substituent, the substituent is not particularly
limited, and examples include an alkoxy group, an aryl group, a
heteroaryl group etc., and these substituents may further have a
substituent. In addition, the carbon number of the alkyl group is
not particularly limited, but from a viewpoint of easy availability
and the cost, the number is preferably 1 or more and 20 or less,
more preferably 1 or more and 8 or less.
[0023] The cycloalkyl group represents a saturated alicyclic
hydrocarbon group, such as a cyclopropyl group, a cyclohexyl group,
a norbornyl group, and an adamantyl group, and may or may not have
a substituent. When the cycloalkyl group has a substituent, the
substituent is not particularly limited, but examples include an
alkyl group, an alkoxy group, an aryl group, a heteroaryl group
etc., and these substituents may further have a substituent.
Explanation regarding these substituents are common to the
following description, unless otherwise is indicated. The carbon
number of the cycloalkyl group is not particularly limited, but a
range of 3 or more and 20 or less is preferable.
[0024] The heterocyclic group represents a group derived from an
aliphatic ring having an atom other than carbon, such as a pyran
ring, a piperidine ring, and an amide ring in the ring, and may or
may not have a substituent. The carbon number of the heterocyclic
group is not particularly limited, but a range of 2 or more and 20
or less is preferable.
[0025] The alkenyl group represents an unsaturated aliphatic
hydrocarbon group containing a double bond, such as a vinyl group,
an allyl group, and a butadienyl group, and may or may not have a
substituent. The carbon number of the alkenyl group is not
particularly limited, but a range of 2 or more and 20 or less is
preferable.
[0026] The cycloalkenyl group represents an unsaturated alicyclic
hydrocarbon group containing a double bond, such as a cyclopentenyl
group, a cyclopentadienyl group, and a cyclohexenyl group, and may
or may not have a substituent. The carbon number of the
cycloalkenyl group is not particularly limited, but a range of 3 or
more and 20 or less is preferable.
[0027] The alkynyl group represents an unsaturated aliphatic
hydrocarbon group containing a triple bond, such as an ethynyl
group, and may or may not have a substituent. The carbon number of
the alkynyl group is not particularly limited, but a range of 2 or
more and 20 or less is preferable.
[0028] The alkoxy group represents a functional group in which one
side of an ether bond is substituted with an aliphatic hydrocarbon
group, such as a methoxy group, an ethoxy group, and a propoxy
group, and may or may not have a substituent. The carbon number of
the alkoxy group is not particularly limited, but a range of 1 or
more and 20 or less is preferable.
[0029] The alkylthio group is such that an oxygen atom of an ether
bond of an alkoxy group is substituted with a sulfur atom, and may
or may not have a substituent. The carbon number of the alkylthio
group is not particularly limited, but a range of 1 or more and 20
or less is preferable.
[0030] The arylether group represents a functional group in which
one side of an ether bond is substituted with an aromatic
hydrocarbon group, such as a phenoxy group, and a naphthoxy group,
and may or may not have a substituent. The carbon number of the
aryl ether group is not particularly limited, but a range of 6 or
more and 40 or less is preferable.
[0031] The arylthioether group is such that an oxygen atom of an
ether bond of an aryl ether group is substituted with a sulfur
atom, and may or may not have a substituent. The carbon number of
the arylthioether group is not particularly limited, but a range of
6 or more and 40 or less is preferable.
[0032] The aryl group represents an aromatic hydrocarbon group,
such as a phenyl group, a naphthyl group, a biphenyl group, an
anthracenyl group, a phenanthryl group, a terphenyl group, and a
pyrenyl group, and may or may not have a substituent. The carbon
number of the aryl group is not particularly limited, but a range
of 6 or more 40 or less is preferable.
[0033] The heteroaryl group represents an aromatic group having one
or more atoms other than carbon in a ring, such as a furanyl group,
a thiophenyl group, a benzofuranyl group, a dibenzofuranyl group, a
pyridyl group, and a quinolinyl group, and may or may not have a
substituent. The carbon number of the heteroaryl group is not
particularly limited, but a range of 2 or more and 30 or less is
preferable.
[0034] The halogen atom represents fluorine, chlorine, bromine or
iodine.
[0035] The alkylcarbonyl group represents a functional group in
which one side of a carbonyl bond is substituted with an aliphatic
hydrocarbon group, such as an acetyl group, and a hexanoyl group,
and may or may not have a substituent. The carbon number of the
alkylcarbonyl group is not particularly limited, but a range of 2
or more and 20 or less is preferable.
[0036] The arylcarbonyl group represents a functional group in
which one side of a carbonyl bond is substituted with an aromatic
hydrocarbon group, such as a benzoyl group, and may or may not have
a substituent. The carbon number of the arylcarbonyl group is not
particularly limited, but a range of 7 or more and 40 or less is
preferable.
[0037] The alkoxycarbonyl group represents a functional group in
which one side of a carbonyl bond is substituted with an alkoxy
group, such as a methoxycarbonyl group, and may or may not have a
substituent. The carbon number of the alkoxycarbonyl group is not
particularly limited, but a range of 2 or more and 20 or less is
preferable.
[0038] The aryloxycarbonyl group represents a functional group in
which one side of a carbonyl bond is substituted with an aryloxy
group, such as a phenoxycarbonyl group, and may or may not have a
substituent. The carbon number of the aryloxycarbonyl group is not
particularly limited, but a range of 7 or more and 40 or less is
preferable.
[0039] The alkylcarbonyloxy group represents a functional group in
which one side of an ether bond is substituted with an
alkylcarbonyl group, such as an acetoxy group, and may or may not
have a substituent. The carbon number of the alkylcarbonyloxy group
is not particularly limited, but a range of 2 or more and 20 or
less is preferable.
[0040] The arylcarbonyloxy group represents a functional group in
which one side of an ether bond is substituted with an arylcarbonyl
group, such as a benzoyloxy group, and may or may not have a
substituent. The carbon number of the arylcarbonyloxy group is not
particularly limited, but a range of 7 or more and 40 or less is
preferable.
[0041] The carbamoyl group, the amino group and the silyl group may
or may not have a substituent. When those groups have a
substituent, examples thereof include an alkyl group, a cycloalkyl
group, an aryl group, and a heteroaryl group, and these
substituents may further have a substituent.
[0042] The case where adjacent groups are bound each other to form
a ring structure will be described referring to the general formula
(1). For example, R.sup.1 and R.sup.2 are bound each other to form
a conjugated or non-conjugated fused ring. Constituent elements of
the fused ring may contain nitrogen, oxygen, sulfur, phosphorus,
and silicone atoms in addition to carbon, and may be further fused
with another ring.
[0043] Then, A of the general formula (1) will be described. An
arylene group represents a divalent (two places of binding sites)
aromatic hydrocarbon group, and may be unsubstituted or
substituted. Examples of a substituent when the arylene group is
substituted, include the alkyl group, a heteroaryl group, and
halogen. Preferable examples of the arylene group include a
phenylene group, a naphthylene group, a biphenylene group, a
phenanthrylene group, an anthrylene group, a terphenylene group, a
pyrenylene group, a fluorenylene group, and a perylenylene
group.
[0044] The heteroarylene group represents a divalent heterocyclic
aromatic ring, and may be unsubstituted or substituted. Preferable
examples of the heteroarylene group include divalent groups derived
from a heterocyclic aromatic ring, such as benzofuran,
dibenzofuran, benzothiophene, dibenzothiophene, benzodithiophene,
benzosilol and dibenzosilol, in addition to a pyridylene group, a
pyrazylene group, a quinolinylene, an isoquinolinylene group, a
quinoxalylene group, an acridinylene group, an indolylene, and a
carbazolylene group.
[0045] In the general formula (1), l and m represent an integer of
0 to 10, and Since by containing the thiophene unit in a structure,
adherability with CNT is improved, and dispersibility of CNT is
improved, l and m are each preferably 1 or more, further preferably
l+m.gtoreq.4. In addition, from a viewpoint of easiness of
synthesis of monomer, and polymerization thereafter, l+m.ltoreq.12
is preferable.
[0046] n represents a polymerization degree of the conjugated
polymer, and is in a range of 2 to 1000. In view of easiness of
attachment to CNT, n is preferably in a range of 3 to 500. In the
present invention, a polymerization degree n is a value obtained
from a weight average molecule weight. The weight average molecule
weight is obtained by measurement using GPC (gel permeation
chromatography), and conversion using a standard sample of
polystyrene.
[0047] In addition, from easiness of formation of the CNT
composite, it is preferable that the conjugated polymer is soluble
in a solvent, and it is preferable that at least one of R.sup.1 to
R.sup.6 is an alkyl group.
[0048] Examples of the conjugated polymers include conjugated
polymers having the following structures.
##STR00002## ##STR00003## ##STR00004## ##STR00005## ##STR00006##
##STR00007## ##STR00008## ##STR00009## ##STR00010## ##STR00011##
##STR00012##
[0049] In addition, the conjugated polymer can be synthesized by
the known method. For example, examples of a method of joining
thiophene with a benzothiadiazole group include a method of
coupling halogenated benzothiadiazole and thiopheneboronic acid or
thiopheneboronic acid ester under a palladium catalyst, and a
method of coupling halogenated benzothiadiazole and a thiophene
Grignard reagent under a nickel or palladium catalyst. In addition,
when other unit and the thiophene unit are joined, halogenated
other unit and the thiophene unit can be coupled by the similar
method. Further, the conjugated polymer can be obtained by
introducing a polymerizable functional group into an end of the
thus obtained monomer, and proceeding polymerization under a
palladium catalyst or a nickel catalyst.
[0050] It is preferable that, in the conjugated polymer, impurities
such as raw materials used in a synthesis process and byproducts
are removed. As method of removing impurities, for example, a
silica gel columngraphy method, a Soxhlet extraction method, a
filtration method, an ion exchange method, and a chelate method can
be used. Two or more kinds of these methods may be combined.
[0051] As CNT, any of monolayer CNT in which one carbon film
(hereinafter, referred to as graphene sheet) is wound in a cylinder
manner, bilayer CNT in which two graphene sheets are wound
concentrically, and multilayer CNT in which a plurality of graphene
sheets are wound concentrically may be used, and two or more kinds
of them may be used. CNT can be obtained by an arc discharge
method, a chemical vapor deposition method (CVD method), a laser
abrasion method etc.
[0052] When used in a semiconductor layer of FET, it is preferable
that the length of CNT is shorter than a distance between a source
electrode and a drain electrode (channel length). An average length
of CNT depends upon a channel length, and is preferably 2 .mu.m or
less, more preferably 0.5 .mu.m or less. Since commercially
available CNT has generally distribution in a length and contains
CNT longer than a channel length in some cases, it is preferable to
add a step of making CNT shorter than a channel length. For
example, a method of cutting CNT into short fibers by acid
treatment with nitric acid, or sulfuric acid, ultrasound treatment,
or freezing grinding method is effective. In addition, combined use
of separation with a filter is further preferable in that a purity
of CNT is improved.
[0053] It is preferable to provide a step of uniformly dispersing
CNT in a solvent, and filtering the dispersion with a filter. CNT
having a size shorter than a channel length is effectively obtained
by obtaining CNT having a size smaller than a filter pore diameter
from a filtrate. In this case, as a filter, a membrane filter is
preferably used. It is enough that the pore diameter of a filter
used in filtration is smaller than a channel length, and the pore
diameter is preferably 0.5 to 10 .mu.m. As another method of
shortening CNT, acid treatment, and freezing grinding treatment are
exemplified.
[0054] In addition, the diameter of CNT is not particularly
limited, but is preferably 1 nm or more and 100 nm or less, more
preferably 50 nm or less.
[0055] The CNT composite of the present invention per se can be
used as a semiconductor layer of FET, and an organic semiconductor
composite containing the CNT composite and an organic semiconductor
can be also preferably used. By uniformly dispersing the CNT
composite in the organic semiconductor, it becomes possible to
realize higher mobility while the properties of the organic
semiconductor itself are maintained.
[0056] The organic semiconductor used in the organic semiconductor
composite of the present invention can be used regardless of a
molecular weight, as far as it is a material exhibiting
semiconductivity. A material having high carrier mobility is
preferable. In addition, since an organic semiconductor which is
soluble in an organic solvent can simply form an organic
semiconductor layer by applying a solution to a substrate or a
film, it is preferable. A kind of the organic semiconductor is not
particularly limited, but examples include polythiophenes such as
poly-3-hexylthiophene, and polybenzothiophene; copolymers
containing a thiophene unit in a main chain such as
poly(2,5-bis(2-thienyl)-3,6-dipentadecylthieno[3,2-b]thioph ene),
poly(4,8-dihexyl-2,6-bis(3-hexylthiophen-2-yl)benzo[1,2-b:4,5-b']dithioph-
ene), poly(4-oethyl-2-(3-oethylthiophen-2-yl)thiazole), and
poly(5,5'-bis(4-octylthiazol-2-yl)-2,2'-bithiophene); polypyrroles;
poly(p-phenylenevinylene)s such as poly(p-phenylenevinylene);
polyanilines; polyacetylenes; polydiacetylenes; polycarbazoles;
polyfurans such as polyfuran, and polybenzofuran; polyheteroaryls
containing a nitrogen-containing aromatic ring as a constitutional
unit, such as pyridine, quinoline, phenanthroline, oxazole, and
oxadiazole; fused polycyclic aromatic compounds such as anthracene,
pyrene, naphthacene, pentacene, hexacene, and rubrene;
nitrogen-containing aromatic compounds such as furan, thiophene,
benzothiophene, dibenzofuran, pyridine, quinoline, phenanthroline,
oxazole, and oxadiazole; aromatic amine derivatives, a
representative of which is
4,4'-bis(N-(3-methylphenyl)-N-phenylamino)biphenyl; biscarbazole
derivatives such as bis(N-allylcarbazole) and
bis(N-alkylcarbazole); pyrazoline derivatives; stilbene-based
compounds; hydrorazone-based compounds; metal pathalocyanines such
as copper phthalocyanine; metal porphyrins such as copper
porphyrin; distyrylbenzene derivatives; aminostyryl derivates;
aromatic acetylene derivatives; fused ring tetracarboxylic acid
diimides such as naphthalene-1,4,5,8-tetracarboxilic acid diimide,
perylene-3,4,9,10-tetracarboxylic acid diimide; organic dyes such
as merocyanine, phenoxazine, and rhodamine. Two or more kinds of
them may be contained. Since the conjugated polymer contained in
the CNT composite contains the thiophene unit, an organic
semiconductor having the thiophene unit in a structure is
preferable.
[0057] Examples of a method of forming an organic semiconductor
composite include a method of mixing a solution containing the CNT
composite, and an organic semiconductor or a solution thereof. In
addition, if necessary, a heating step for promoting mixing, or an
ultrasound irradiation step may be added, or a step of removing a
solid component such as filtration may be added.
[0058] The content of the CNT composite in the organic
semiconductor composite is preferably 0.01 part by weight or more
and 3 parts by weight or less, more preferably 1 part by weight or
less relative to 100 parts by weight of the organic semiconductor.
By addition of the CNT composite in this range, mobility of the
organic semiconductor can be considerably increased. However, when
the CNT composite is mixed at an amount exceeding 3 parts by
weight, a ratio of contact between CNTs is increased, and
electrical conductivity of the organic semiconductor composite is
increased, approaching metal state and, therefore, this is not
preferable.
[0059] Then, the organic FET using the CNT composite of the present
invention will be described. The organic FET of the present
invention is an organic field-effect transistor having a gate
electrode, a gate insulating layer, a semiconductor layer, a source
electrode and a drain electrode, and the semiconductor layer
contains the CNT composite of the present invention.
[0060] FIG. 1 and FIG. 2 are a schematic cross-sectional view
showing an example of FET of the present invention. In FIG. 1, a
source electrode 5 and a drain electrode 6 are formed on a
substrate 1 having a gate electrode 2 covered with a gate
insulating layer 3, and a semiconductor layer 4 containing the CNT
composite is further formed thereon. In FIG. 2, the semiconductor
layer 4 containing the CNT composite of the present invention is
formed on the substrate 1 having the gate electrode 2 covered with
the gate insulating layer 3, and the source electrode 5 and the
drained electrode 6 are further formed thereon.
[0061] Examples of the material used in the substrate 1 include
inorganic materials such as a silicon wafer, a glass, and an
alumina sintered body, and organic materials such as polyimide,
polyester, polycarbonate, polysulfone, polyethersulfone,
polyethylene, polyphenylene sulfide, and polyparaxylene.
[0062] Examples of a material used in the gate electrode 2, the
source electrode 5 and the drain electrode 6 include electrically
conductive metal oxides such as tin oxide, indium oxide, and tin
indium oxide (ITO); metals such as aluminum, indium, chromium.
lithium, sodium, potassium, cesium, calcium, magnesium, palladium,
molybdenum, amorphous silicon and polysilicon; alloys thereof;
inorganic electrically conductive materials such as copper iodide
and copper sulfide; electrically conductive polymers such as
polythiophene, polypyrrole, polyaniline, and a complex of
polyethylenedioxythiophene and polystyrenesulfonic acid, which were
doped with iodine etc., to improve electrical conductivity, being
not limiting. Alternatively, a plurality of materials may be used
for laminating or mixing.
[0063] Examples of a method of forming the gate electrode 2, the
source electrode 5 and the drain electrode 6 include resistance
heating deposition, electron beam, sputtering, plating, CVD, ion
plating coating, inkjet and printing, and there is not particularly
limitation as far as conduction can be taken. In addition, as a
method of forming an electrode pattern, an electrode film
manufactured by the above method may be pattern-formed into a
desired shape by the known photolithography, or may be
pattern-formed via a desired shaped mask at deposition or
sputtering of an electrode material.
[0064] A material used in the gate insulating layer 3 is not
particularly limited, but examples include inorganic materials such
as silicon oxide, and alumina; organic polymer materials such as
polyimide, polyvinyl alcohol, polyvinyl chloride, polyethylene
terephthalate, polyvinilidene fluoride, polysiloxane, and polyvinyl
phenol (PVP); mixtures of inorganic material powders and organic
polymer materials. The film thickness of the gate insulating layer
is preferably 50 nm to 3 .mu.m, more preferably 100 nm to 1 .mu.m.
The gate insulating layer may be a monolayer or multilayer. In
addition, one layer may be formed of a plurality of insulating
materials, or a plurality of insulating materials may be laminated
to form a plurality of gate insulating layers.
[0065] Examples of a method of forming the gate insulating layer is
not particularly limited, but include methods such as resistance
heating deposition, electron beam, sputtering, CVD, ion plating,
coating, inkjet and printing, and the method can be used depending
on a material.
[0066] In FET of the present invention, the semiconductor layer 4
contains the CNT composite of the present invention. By inclusion
of the CNT composite of the present invention in the semiconductor
layer, hysteresis can be reduced while high mobility is
retained.
[0067] Further, in the semiconductor layer 4, the organic
semiconductor composite can be also preferably used. That is, it is
preferable that, in addition to the CNT composite, the organic
semiconductor is further contained in the semiconductor layer 4. By
dispersing the CNT composite in the organic semiconductor
uniformly, it becomes possible to realize higher mobility while
properties of the organic semiconductor itself are maintained.
[0068] The semiconductor layer 4 may further contain an insulating
material. Examples of the insulating material used herein are not
limited to, but include poly(methyl methacrylate), polycarbonate,
and polyethylene terephthalate.
[0069] The film thickness of the semiconductor layer 4 is
preferably 5 nm or more and 100 nm or less. By adopting this range
of a film thickness, formation of uniform film becomes easy.
Furthermore, a current between source.cndot.drain which cannot be
controlled by a gate voltage is suppressed, and an on off ratio of
the organic FET can be enhanced. A film thickness can be measured
with an atom force microscope, or by ellipsometry. In addition, the
semiconductor layer 4 may be a monolayer or plural layers. In the
case of the plural layers, a layer comprising a plurality of CNT
composites of the present invention may be laminated, or a layer
comprising the CNT composite and a layer comprising the organic
semiconductor may be laminated.
[0070] As a method of forming the semiconductor layer 4, a dry
method such as resistance heating deposition, electron beam,
sputtering, and CVD can be also used, but from a viewpoint of the
manufacturing cost and adaptability to a great area, it is
preferable to use a coating method. Specifically, a spin coating
method, a blade coating method, a slit die coating method, a screen
printing method, a bar coater method, a casting method, a printing
transference method, an immersion pulling method, and an inkjet
method can be preferably used. The coating method can be selected
depending on coated film properties to be obtained, such as coated
film thickness control and orientation control. Thereupon, examples
of a solvent used in a semiconductor coating solution containing
the CNT composite include tetrahydrofuran, toluene, xylene,
1,2,3-trimethylbenzene, 1,2,3,5-tetramethylbenzene,
1,3-diethylbenzene, 1,4-diethylbenzene, 1,3,5-triethylbenzene,
1,3-diisopropylbenzene, 1,4-isopropylbenzene, 1,4-dipropylbenzene,
butylbenzene, isobutylbenzene, 1,3,5-triisopropylbenzene,
dichloromethane, dichloroethane, chloroform, chlorobenzene,
dichlorobenzene, o-chlorotoluene, 1,2-dihydronaphthalene,
1,2,3,4-tetrahydronaphthalene, ethyl benzoate, ethyl
2,4,6-trimethylbenzoate, ethyl 2-ethoxybenzoate, o-toluidine,
m-toluidine, and p-toluidine. Two or more kinds of these solvents
may be used. In addition, the formed coated film may be
annealing-treated under the atmospheric pressure, under reduced
pressure or under the inert gas atmosphere (under nitrogen or argon
atmosphere).
[0071] In addition, an orienting layer may be provided between the
gate insulating layer 3 and the semiconductor layer 4. In the
orienting layer, the known materials such as a silane compound, a
titanium compound, an organic acid, and a heterorganic acid can be
used and, among them, a silane compound is preferable.
[0072] In view of resistance of the orienting layer, the film
thickness of the orienting layer is preferably 10 nm or less,
further preferably, a monomolecular film. In addition, the
orienting layer also includes, for example, an orienting layer
formed by chemically binding the organic silane compound and a gate
insulating layer surface. By chemically reacting a silyl group and
a gate insulating layer surface, a dense and firm film can be
formed. When an unreacted silane compound is laminated on a firm
film after a reaction, an unreacted silane compound is removed by
washing, and a monomolecular film formed by chemically binding a
silyl group and a gate insulating layer surface can be
obtained.
[0073] In the present invention, it is preferable that a second
insulating layer formed on an opposite side of the gate insulating
layer relative to the semiconductor layer is possessed. By
possession of the second insulating layer, hysteresis can be
further improved while high mobility and a high on off ratio are
retained, and a threshold voltage can be reduced. Herein, on an
opposite side of the gate insulating layer relative to the
semiconductor layer refers to, for example, a lower side of the
semiconductor layer when a gate insulating layer is possessed on an
upper side of the semiconductor layer. That is, it is meant that
the gate insulating layer and the second insulating layer are
possessed on both of a front side and a back side of a film plane
of the semiconductor layer, respectively. By formation of the
second insulating layer, it is presumed that hysteresis and a
threshold voltage can be improved by interrupting the semiconductor
layer from oxygen and moisture and, at the same time, removing a
moisture adsorbed onto a semiconductor layer surface.
[0074] A material used in the second insulating layer is not
particularly limited, but examples include specifically inorganic
materials such as silicon oxide, and alumina, organic polymer
materials such as polyimide and a derivative thereof, polyvinyl
alcohol, polyvinyl chloride, polyethylene terephthlate,
polyvinylidene fluoride, polysiloxane and a derivative thereof,
polyvinylphenol and a derivative thereof; or mixtures of inorganic
material powders and organic polymer materials, and mixtures of
organic low-molecular materials and organic polymer materials.
Among them, it is preferable that organic polymer materials which
can be manufactured by a coating method such as inkjet are used.
Particularly, when organic polymer materials selected from the
group consisting of polyfluoroethylene, polynorbornene,
polysiloxane, polyimide, polystyrene, polycarbonate and a
derivative thereof, polyacrylic acid derivative, a polymethacrylic
acid derivative, and a copolymer containing them are used, the
effect of reducing hysteresis and a threshold voltage is increased,
being preferable. A polyacrylic acid derivative, a polymethacrylic
acid derivative, or a copolymer containing them is particularly
preferable.
[0075] The film thickness of the second insulating layer is
generally 50 nm to 10 .mu.m, preferably 100 nm to 3 .mu.m. The
second insulating layer may be a monolayer or multilayer. In
addition, one layer may be formed of a plurality of insulating
materials, or the second insulating layer may be formed by
laminating a plurality of insulating materials.
[0076] A method of forming the second insulating layer is not
particularly limited, but dry methods such as resistance heating
deposition, electron beam, sputtering, and CVD can be also used,
but from a viewpoint of the manufacturing cost and adaptation to a
great area, it is preferable to use a coating method. As the
coating method, specifically, a spin coating method, a blade
coating method, a slit die coating method, a screen printing
method, a bar coater method, a casting method, a printing
transference method, an immersion pulling method, an inkjet method,
a drop casting method can be preferably used. The coating method
can be selected depending on the coated film properties to be
obtained, such as coated film thickness control and orientation
control.
[0077] A solvent for dissolving an insulating material used in the
second insulating layer is not particularly limited, but examples
include ethers such as ethylene glycol monomethyl ether, ethylene
glycol monoethyl ether, propylene glycol monomethyl ether,
propylene glycol monoethyl ether, propylene glycol mono n-butyl
ether, propylene glycol mono t-butyl ether, ethylene glycol
dimethyl ether, ethylene glycol diethyl ether, ethylene glycol
dibutyl ether, and diethylene glycol ethyl methyl ether; esters
such as ethylene glycol monoethyl ether acetate, propylene glycol
monomethyl ether acetate, propyl acetate, butyl acetate, isobutyl
acetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate,
methyl lactate, ethyl lactate, and butyl lactate; ketones such as
acetone, methyl ethyl ketone, methyl propyl ketone, methyl butyl
ketone, methyl isobutyl ketone, cyclopentatnone, and 2-heptanone;
alcohols such as butyl alcohol, isobutyl alcohol, pentanol,
4-methyl-2-pentanol, 3-methyl-2-butanol, 3-methyl-3-methoxybutanol,
and diacetone alcohol; aromatic hydrocarbons such as toluene, and
xylene. Two or more kinds of them may be used. Among them, it is
preferable that a solvent having a boiling point of 110 to
200.degree. C. at one atm is contained. When a boiling point is
110.degree. C. or higher, vaporization of a solvent is suppressed
at solution coating, and coating property becomes good. When a
boiling point is 200.degree. C. or lower, a solvent remaining in an
insulating film is present at a small amount, and an insulating
layer having good heat resistance and chemical resistance is
obtained. In addition, the formed coated film may be
annealing-treated under the atmospheric pressure, under reduced
pressure, or under the inert gas atmosphere (under nitrogen or
argon atmosphere).
[0078] In the present invention, it is preferable that at least one
layer of the gate insulating layer, the semiconductor layer and the
second insulating layer contains an amine compound. By attachment
of the amine compound to the CNT composite, extra carries are
trapped, and it becomes possible to further reduce a threshold
voltage. The amine compound is not particularly limited, but
examples include methylamine, trimethylamine, triethylamine,
ethyldiisopropylamine, hexylamine, dodecylamine,
3-aminopropyltriethoxysilane, 2-methoxymethylamine, piperidine,
piperazine, N-methylpiperadone, aniline, toluidine, pyridylamine,
aminoquinoline, benzylamine, julolidine, triphenylamine,
N-ethylcarbazole, polyvinylcarbazole, polypyrolle, polyaniline,
ethylenediamine, 4,4'-bis(diphenylamino)biphenyl, ethyl
3-aminobenzoate, and pyrimidopyrimidine. The amine compound may be
contained in any of the gate insulating layer, the semiconductor
layer and the second insulating layer and, when contained in the
second insulating layer, a threshold voltage can be considerably
reduced without deteriorating other properties, being
preferable.
[0079] The amount of addition of the amine compound to the second
insulating layer is preferably 0.1 part by weight or more and 20
parts by weight or less, further preferably 0.5 part by weight or
more and 10 parts by weight or less relative to 100 parts by weight
of an insulating material used in the second insulating layer.
[0080] The amine compound may be added to a part of the second
insulating layer, or may be contained in a whole of the second
insulating layer. When added to a part of the second insulating
layer, it is preferable that the amine compound is added on a
semiconductor layer side so that the CNT composite in the
semiconductor layer, and the amine compound can interact.
[0081] The thus formed FET can control a current flowing between
the source electrode and the drain electrode (current between
source and drain) by changing a gate voltage. Mobility of FET can
be calculated using the following (a) equation.
.mu.=(.delta.Id/.delta.Vg)LD/(W.epsilon..sub.r.epsilon.Vsd) (a)
[0082] Wherein, Id is a current between source and drain (A), Vsd
is a voltage between source and drain (V), Vg is a gate voltage
(V), D is a thickness of a gate insulating layer (m), L is a
channel length (M), W is a channel width (m), .epsilon..sub.r is a
specific dielectric constant of a gate insulating layer (3.3 in
case of polysiloxane), and E is a vacuum dielectric constant
(8.85.times.10.sup.-12 F/m).
[0083] In addition, an on off ratio can be obtained from a ratio Id
(on current)/Id (off current) of a maximum of Id (Id (on current))
and minimum of Id (Id (off current)) when the gate voltage is
changed in the predetermined range.
[0084] Hysteresis can be obtained from an absolute value of a
difference between a gate voltage Vg.sup.1 at Id=10.sup.-8 (A) upon
application of Vg from positive to negative, and a gate voltage
Vg.sup.2 at Id=10.sup.-8 (A) upon application of Vg from negative
to positive |Vg.sup.1-Vg.sup.2|.
[0085] A threshold voltage can be obtained from an intersection
between an extension line of a linear part and a Vg axis in an
Id-Vg graph.
EXAMPLES
[0086] The present invention will be further specifically described
below based on Examples. The present invention is not limited to
the following Examples.
[0087] Herein, for .sup.1H-NMR measurement, an FT-NMR apparatus
(JEOL JNM-EX270 manufactured by JEOL Ltd.), was used.
[0088] In addition, an average molecular weight (number average
molecular weight, weight average molecular weight) was measured
using a GPC apparatus (high speed GPC apparatus HLC 8220GPC,
manufactured by TOSOH) by pumping chloroform as a mobile phase.
Using a calibration line obtained by measuring a relationship
between an elution time and a molecular weight using a polystyrene
standard sample, an average molecular weight of a sample was
calculated by an absolute calibration line method. A polymerization
degree n was calculated by the following equation.
Polymerization degree n=[(weight average molecular
weight)/(molecular weight of one monomer unit)]
Synthesis Example 1
Synthesis of Compound [21]
[0089] The compound [21] was synthesized by a method shown in the
formula 1.
##STR00013## ##STR00014## ##STR00015##
[0090] To 150 ml of 48% hydrobromic acid were added 4.3 g of a
compound (1-a) (manufactured by Tokyo Chemical Industry Co., Ltd.)
and 10 g of bromine (manufactured by Wako Pure Chemical Industries,
Ltd.), and the mixture was stirred at 120.degree. C. for 3 hours.
The reaction was cooled to room temperature, and the precipitated
solid was filtered through a glass filter, and washed with 1000 ml
of water and 100 ml of acetone. The resulting solid was
vacuum-dried at 60.degree. C. to obtain 6.72 g of a compound
(1-b).
[0091] In 100 ml of dimethylformamide was dissolved 10.2 g of a
compound (1-c), 9.24 g of N-bromosuccinimide (manufactured by Wako
Pure Chemical Industries, Ltd.) was added, and the mixture was
stirred at room temperature for 3 hours under a nitrogen
atmosphere. To the resulting solution were added 200 ml of water,
200 ml of hexane and 200 ml of dichloromethane, and an organic
layer was taken. The resulting organic layer was washed with 200 ml
of water, and dried over magnesium sulfate. The resulting solution
was purified by column chromatography (filler: silica gel, eluent:
hexane) to obtain 14.4 g of a compound (1-d).
[0092] In 200 ml of tetrahydrofuran was dissolved 14.2 g of the
compound (1-d), and the solution was cooled to -80.degree. C. After
35 ml of n-butyllithium (1.6 M hexane solution) (manufactured by
Wako Pure Chemical Industries, Ltd.) was added, a temperature was
raised to -50.degree. C., and the solution was cooled to
-80.degree. C. again.
2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (13.6 ml)
(manufactured by Wako Pure Chemical Industries, Ltd.) was added, a
temperature was raised to room temperature, and the mixture was
stirred for 4 hours under a nitrogen atmosphere. To the resulting
solution were added 200 ml of a 1 N aqueous ammonium chloride
solution, and 200 ml of ethyl acetate, and the organic layer was
taken. The resulting organic layer was washed with 200 ml of water,
and dried over magnesium sulfate. The resulting solution was
purified by column chromatography (filler: silica gel, eluent:
hexane/dichloromethane) to obtain 14.83 g of a compound (1-e).
[0093] To 200 ml of dimethylformamide were added 14.83 g of the
compound (1-e), 6.78 g of 5,5'-dibromo-2,2'-bithiophene
(manufactured by Tokyo Chemical Industry Co., Ltd.), 26.6 g of
potassium phosphate (manufactured by Wako Pure Chemical Industries,
Ltd.) and 1.7 g of
[bis(diphenylphosphino)ferrocene]dichloropalladium (manufactured by
Aldrich) were further added under a nitrogen atmosphere, and the
mixture was stirred at 100.degree. C. for 4 hours. To the resulting
solution were added 500 ml of water and 300 ml of ethyl acetate, an
organic layer was taken. The resulting organic layer was washed
with 500 ml of water, and dried over magnesium sulfate. The
resulting solution was purified by column chromatography (filler:
silica gel, eluent: hexane) to obtain 4.53 g of a compound
(1-f)
[0094] In 40 ml of tetrahydrofuran was dissolved 4.53 g of the
compound (1-f), and the solution was cooled to -80.degree. C. After
6.1 ml of n-butyllithium (1.6 M hexane solution) was added, a
temperature was raised to -5.degree. C., and the solution was
cooled to -80.degree. C. again.
2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.3 ml) was
added, a temperature was raised to room temperature, and the
mixture was stirred for 2 hours under a nitrogen atmosphere. To the
resulting solution were added 150 ml of a 1 N aqueous ammonium
chloride solution and 200 ml of ethyl acetate, and the organic
layer was taken. The resulting organic layer was washed with 200 ml
of water, and dried over magnesium sulfate. The resulting solution
was purified by column chromatography (filler: silica gel, eluent:
dichloromethane/hexane) to obtain 2.31 g of a compound (1-g).
[0095] To 17 ml of dimethylformamide were added 0.498 g of the
compound (1-b) and 2.31 g of the compound (1-g), 2.17 g of
potassium phosphate and 0.14 g of
[bis(diphenylphosphino)ferrocene]dichloropalladium (manufactured by
Aldrich) were further added under a nitrogen atmosphere, and the
mixture was stirred at 90.degree. C. for 7 hours. To the resulting
solution were added 200 ml of water and 100 ml of chloroform, and
the organic layer was taken. After the resulting organic layer was
washed with 200 ml of water, and dried over magnesium sulfate. The
resulting solution was purified by column chromatography (filler:
silica gel, eluent: dichloromethane/hexane) to obtain 1.29 g of a
compound (1-h). The results of .sup.1H-NMR of the compound (1-h)
are shown. .sup.1H-NMR (CD.sup.2Cl.sup.2, (d-ppm)): 8.00 (s, 2H),
7.84 (s, 2H), 7.20-7.15 (m, 8H), 7.04 (d, 2H), 6.95 (d, 2H), 2.88
(t, 4H), 2.79 (t, 4H), 1.77-1.29 (m, 48H), 0.88 (m, 12H)
[0096] In 15 ml of chloroform was dissolved 0.734 g of the compound
(1-h), 0.23 g of N-bromosuccinimide/10 ml of dimethylformamide were
added, and the mixture was stirred at room temperature for 9 hours
under a nitrogen atmosphere. To the resulting solution were added
100 ml of water and 100 ml of chloroform, and the organic layer was
taken. The resulting organic layer was washed with 200 ml of water,
and dried over magnesium sulfate. The resulting solution was
purified by column chromatography (filler: silica gel, eluent:
dichloromethane/hexane) to obtain 0.58 g of a compound (1-i).
[0097] To 7 ml of 1,4-dioxane were added 0.5 g of a compound (1-j),
0.85 g of bis(pinacolato)diboron (manufactured by BASF), and 0.86 g
of potassium acetate (manufactured by Wako Pure Chemical
Industries, Ltd.), and 0.21 g of
[bis(diphenylphosphino)ferrocene]dichloropalladium was further
added under a nitrogen atmosphere, and the mixture was stirred at
80.degree. C. for 7 hours. To the resulting solution were added 100
ml of water and 100 ml of ethyl acetate, and the organic layer was
taken. The resulting organic layer was washed with 100 ml of water,
and dried over magnesium sulfate. The resulting solution was
purified by column chromatography (filler: silica gel, eluent:
dichloromethane) to obtain 57 mg of a compound (1-k).
[0098] In 6 ml of toluene were dissolved 93 mg of the compound
(1-i), and 19.3 mg of the compound (1-k). Two milliliter of water,
0.18 g of potassium carbonate, 7.7 mg of
tetrakis(triphenylphosphine)palladium (0) (manufactured by Tokyo
Chemical Industry Co., Ltd.) and one droplet of Aliquat (R) 336
(manufactured by Aldrich) were added thereto, and the mixture was
stirred at 100.degree. C. for 25 hours under a nitrogen atmosphere.
Then, 40 mg of phenylboronic acid was added, and the mixture was
stirred at 100.degree. C. for 7 hours. To the resulting solution
was added 50 ml of methanol, and the produced solid was filtered,
and washed sequentially with methanol, water, methanol, and
acetone. The resulting solid was dissolved in chloroform, passed
through a silica gel short column (eluent: chloroform), and
concentrated to dryness to obtain 30 mg of a compound [21]. A
weight average molecular weight was 4367, a number average
molecular weight was 3475, and a polymerization degree n was
3.1.
Synthesis Example 2
Synthesis of Compound [22]
[0099] The compound [22] was synthesized by a method shown in the
formula 2.
##STR00016##
[0100] To 7 ml of 1,4-dioxane were added 0.34 g of a compound
(2-a), 0.85 g of bis(pinacolato) diboron, and 0.86 g of potassium
acetate, 0.21 g of [bis(diphenylphosphino)
ferrocene]dichloropalladium was further added under a nitrogen
atmosphere, and the mixture was stirred at 80.degree. C. for 9
hours. To the resulting solution were added 100 ml of water and 100
ml of ethyl acetate, and the organic layer was taken. The resulting
organic layer was washed with 100 ml of water, and dried over
magnesium sulfate. The resulting solution was purified by column
chromatography (filler: silica gel, eluent: dichloromethane) to
obtain 167 mg of a compound (2-b).
[0101] In 6 ml of toluene were dissolved 110 mg of the compound
(1-i) and 17 mg of the compound (2-b). Two milliliter of water,
0.22 g of potassium carbonate, 9 mg of tetrakis
(triphenylphosphine) palladium (0) and one droplet of Alquat (R)
336 (manufactured by Aldrich) were added thereto, and the mixture
was stirred at 100.degree. C. for 45 hours under a nitrogen
atmosphere. Then, 40 mg of phenylboronic acid was added, and the
mixture was stirred at 100.degree. C. for 4 hour's. To the
resulting solution was added 50 ml of methanol, and the produced
solid was filtered, and washed sequentially with methanol, water,
methanol and acetone. The resulting solid was dissolved in
chloroform, passed through a silica gel short column (eluent:
chloroform), and concentrated to dryness to obtain 75 mf of a
compound [22]. A weight average molecular weight was 8691, a number
average molecular weight was 5676, and polymerization degree n was
6.7.
Synthesis Example 3
Synthesis of Compound [23]
[0102] The compound [23] was synthesized by a method shown in the
formula 3.
##STR00017##
[0103] In 5 ml of toluene were dissolved 57 mg of the compound
(1-i) and 18 mg of a compound (3-a). Two milliliter of water, 0.11
g of potassium carbonate, 4.7 mg of
tetrakis(triphenylphosphine)palladium (0) and one droplet of
Aliquat (R) 336 (manufactured by Aldrich) were added thereto, and
the mixture was stirred at 100.degree. C. for 75 hours under a
nitrogen atmosphere. Then, 40 mg of phenylboronic acid was added,
the mixture was stirred at 100.degree. C. for 5 hours. To the
resulting solution was added 50 ml of methanol, and the produced
solid was filtered, and washed sequentially with methanol, water,
methanol and acetone. The resulting solid was dissolved in
chloroform, passed through a silica gel short column (eluent:
chloroform), and concentrated to dryness to obtain 55 mg of a
compound [23]. A weight average molecular weight was 43230, a
number average molecular weight was 14419, and a polymerization
degree n was 26.5.
Synthesis Example 4
[0104] The compound [24] was synthesized by a method shown in the
formula 4.
##STR00018##
[0105] To 200 ml, of acetone were added 6.33 g of a compound (4-a),
10 g of 1-iodootane (manufactured by Wako Pure Chemical Industries,
Ltd.) and 2.27 g of NaOH, and the mixture was heated to reflux for
10 hours under a nitrogen atmosphere. To the resulting solution
were added water and hexane, and the organic layer was taken. The
resulting organic layer was washed with water, and dried over
magnesium sulfate. The resulting solution was purified by column
chromatography (filler: silica gel, eluent: dichloromethane/hexane)
to obtain 4.82 g of a compound (4-b).
[0106] In 120 ml of dimethylformamide was dissolved 4.82 g of the
compound (4-b), 6.47 g of N-bromosuccinimide was added, and the
mixture was stirred at 50.degree. C. for 10 hours. To the resulting
solution were added water and dichloromethane, and the organic
layer was taken. The resulting organic layer was washed with water,
and dried over magnesium sulfate. The resulting solution was
purified by column chromatography (filler: silica gel, eluent:
dichloromethane/hexane) to obtain 6.53 g of a compound (4-c)
[0107] To 18 ml of 1,4-dioxane were added 1.6 g of the compound
(4-c), 2.32 g of bis(pinacolato)diboron and 2.2 g of potassium
acetate, 0.54 g of
[bis(diphenylphosphino)ferrocene]dichloropalladium was further
added under a nitrogen atmosphere, and the mixture was stirred at
80.degree. C. for 9 hours. To the resulting solution were added 100
ml of water and 100 ml of ethyl acetate, and the organic layer was
taken. The resulting organic layer was washed with 100 ml of water,
and dried over magnesium sulfate. The resulting solution was
purified by column chromatography (filler: silica gel, eluent:
dichloromethane/hexane) to obtain 1.03 g of a compound (4-d).
[0108] In 8 ml of toluene were dissolved 99 mg of the compound
(1-i) and 30 mg of the compound (4-d). Three milliliter of water,
0.195 g of potassium carbonate, 8.1 mg of tetrakis
(triphenylphosphine)palladium (0) and one droplet of Aliquat (R)
336 (manufactured by Aldrich) were added thereto, and the mixture
was stirred at 100.degree. C. for 92 hours under a nitrogen
atmosphere. Then, 34 mg of phenylboronic acid was added, and the
mixture was stirred at 100.degree. C. for 6 hours. To the resulting
solution was added 50 ml of methanol, and the produced solid was
filtered, and washed sequentially with methanol, water, methanol
and acetone. The resulting solid was dissolved in chloroform,
passed through a silica gel short column (eluent: chloroform), and
concentrated to dryness to obtain 85 mg of a compound [24]. A
weight average molecular weight was 9380, a number average
molecular weight was 5410, and a polymerization degree n was
6.2.
Synthesis Example 5
[0109] A compound [33] was synthesized by a method shown in the
formula 5.
##STR00019## ##STR00020## ##STR00021##
[0110] To 40 ml of 1,4-dioxane were added 2.0 g of the compound
(1-b) and 4.3 g of bis(pinacolato)diboron, 4.0 g of potassium
acetate and 1.0 g of
[bis(diphenylphosphino)ferrocene]dichloropalladium were added under
a nitrogen atmosphere, and the mixture was stirred at 80.degree. C.
for 8 hours. To the resulting solution were added 200 ml of water
and 200 ml of ethyl acetate, and the organic layer was taken. The
resulting organic layer was washed with 400 ml of water, and dried
over magnesium sulfate. The resulting solution was purified by
column chromatography (filler: silica gel, eluent:
dichloromethane/ethyl acetate) to obtain 1.3 g of a compound
(5-a).
[0111] In 250 ml of tetrahydrofuran was dissolved 18.3 g of a
compound (5-b), and the solution was cooled to -80.degree. C. After
45 ml of n-butyllithium (1.6 M hexane solution) was added, a
temperature was raised to -50.degree. C., and the solution was
cooled to -80.degree. C. again.
2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (18.6 ml) was
added, a temperature was raised to room temperature, and the
mixture was stirred for 6 hours under a nitrogen atmosphere. To the
resulting solution were added 200 ml of a 1 N aqueous ammonium
chloride solution and 200 ml of ethyl acetate, and the organic
layer was taken. The resulting organic layer was washed with 200 ml
of water, and dried over magnesium sulfate. The resulting solution
was purified by column chromatography (filler: silica gel, eluent:
hexane/dichloromethane) to obtain 16.66 g of a compound (5-c).
[0112] To 100 ml of dimethylformamide were added 2.52 g of the
compound (5-b) and 3.0 g of the compound (5-c), 13 g of potassium
phosphate and 420 mg of
[bis(diphenylphosphino)ferrocene]dichloropalladiume was added under
a nitrogen atmosphere, and the mixture was stirred at 90.degree. C.
for 5 hours. To the resulting solution were added 200 ml of water
and 100 ml of hexane, and the organic layer was taken. The
resulting organic layer was washed with 400 ml of water, and dried
over magnesium sulfate. The resulting solution was purified by
column chromatography (filler: silica gel, eluent: hexane) to
obtain 2.71 g of a compound (5-d).
[0113] In 8 ml of dimethylformamide was dissolved 2.71 g of a
compound (5-d), a solution of 2.88 g of N-bromosuccinimide in
dimethylformamide (16 ml) was added, and the solution was stirred
at 5.degree. C. to 10.degree. C. for 9 hours. To the resulting
solution were added 150 ml of water and 100 ml of hexane, and the
organic layer was taken. The resulting organic layer was washed
with 300 ml of water, and dried over magnesium sulfate. The
resulting solution was purified by column chromatography (filler:
silica gel, eluent: hexane) to obtain 3.76 g of a compound
(5-e).
[0114] To 70 ml of dimethylformamide were added 3.76 g of the
compound (5-e) and 4.71 g of the compound (5-c), 19.4 g of
potassium phosphate and 310 mg of [bis(diphenylphosphino)
ferrocene]dichloropalladium were added under a nitrogen atmosphere,
and the mixture was stirred at 90.degree. C. for 9 hours. To the
resulting solution were added 500 ml of water and 200 ml of hexane,
and the organic layer was taken. The resulting organic layer was
washed with 300 ml of water, and dried over magnesium sulfate. The
resulting solution was purified by column chromatography (filler:
silica gel, eluent: hexane) to obtain 4.24 g of a compound
(5-f).
[0115] In 20 ml of chloroform was dissolved 520 mg of the compound
(5-f), a solution of 280 mg of N-bromosuccinimide in
dimethylformamide (10 ml) was added, and the solution was stirred
at 5.degree. C. to 10.degree. C. for 5 hours. To the resulting
solution were added 150 ml of water and 100 ml of dichloromethane,
and the organic layer was taken. The resulting organic layer was
washed with 200 ml of water, and dried over magnesium sulfate. The
resulting solution was purified by column chromatography (filler:
silica gel, eluent: hexane) to obtain 610 mg of a compound
(5-g).
[0116] In 30 ml of toluene were dissolved 280 mg of the compound
(5-a) and 596 mg of the compound (5-g). Ten milliliter of water,
1.99 g of potassium carbonate, 83 mg of
tetrakis(triphenylphosphine)palladium (0) and one droplet of
Aliquat (R) 336 (manufactured by Aldrich) were added thereto, and
the mixture was stirred at 100.degree. C. for 20 hours under a
nitrogen atmosphere. To the resulting solution was added 100 ml of
methanol, and the produced solid was filtered, and washed
sequentially with methanol, water, acetone and hexane. The
resulting solid was dissolved in 200 ml of chloroform, passed
through a silica gel short column (eluent: chloroform),
concentrated to dryness, and washed sequentially with methanol,
acetone and methanol to obtain 480 mg of a compound [33]. A weight
average molecular weight was 29398, a number average molecular
weight was 10916, and a polymerization degree n was 36.7.
Synthesis Example 6
Synthesis of Compound [39]
[0117] The compound [39] was synthesized by a method shown in the
formula 6.
##STR00022## ##STR00023##
[0118] To 6.15 g of ethyl formate (6-a) (manufactured by Tokyo
Chemical Industry Co., Ltd.) was added 125 ml of tetrahydrofuran,
the mixture was cooled to -78.degree. C., and 250 ml of a solution
of octylmagnesium bromide in tetrahydrofuran having a concentration
of 1.0M (manufactured by Tokyo Chemical Industry Co., Ltd.) was
added dropwise over 1 hour while a reaction solution was retained
at -78.degree. C. After completion of addition, the reaction
solution was stirred at room temperature for 5 hours. Methanol (50
ml) was added to inactivate excessive octylmagnesium bromide, and
tetrahydrofuran was distilled off under reduced pressure. After 120
ml of diethyl ether was added, this was washed with 100 ml of an
aqueous saturated ammonium chloride solution and, then, 100 ml of
an aqueous saturated sodium chloride solution. After the organic
layer was dried over anhydrous magnesium sulfate, a solvent was
distilled off under reduced pressure. The residue was purified by
column chromatography (filler: silica gel, eluent: hexane/ethyl
acetate=10/1) to obtain 16.9 g of a compound (6-b).
[0119] To 80 ml of dichloromethane were added 10.0 g of the
compound (6-b), 5.1 g of triethylamine (manufactured by Wako Pure
Chemical Industries, Ltd.) and 5 ml of pyridine (manufactured by
Wako Pure Chemical Industries, Ltd,) and 8.92 g of
paratoluenesulfonyl chloride was added while stirring at 0.degree.
C. After the reaction solution was stirred at 0.degree. C. for 1
hour, it was stirred at room temperature for 12 hours. Fifty
milliliter of water was added, and the mixture was further stirred
at room temperature for 30 minutes, followed by extraction with 80
ml of dichloromethane two times. The organic layer was dried over
anhydrous magnesium sulfate, and a solvent was distilled off under
reduced pressure. The residue was purified by column chromatography
(filler: silica gel, eluent: hexane/ethyl acetate=10/1) to obtain
9.2 g of a compound (6-c).
[0120] To 25.0 g of 4,4'-dibromodiphenyl (6-d) (manufactured by
Tokyo Chemical Industry Co., Ltd.) was added 375 ml of acetic acid
(manufactured by Wako Pure Chemical Industries, Ltd.) 120 ml of
fuming nitric acid (manufactured by Wako Pure Chemical Industries,
Ltd.) was slowly added while stirring at 100.degree. C. and,
subsequently, 10 ml of water was added to the reaction solution.
The reaction solution was stirred at 100.degree. C. for 1 hour,
cooled to room temperature, and allowed to stand at room
temperature for 5 hours. The precipitated solid was filtered, and
washed with water and ethanol. The crude product was recrystallized
from ethanol to obtain 17.0 g of a compound (6-e).
[0121] To 11.0 g of the compound (6-e) was added 40 ml of triethyl
phosphite, and the mixture was stirred at 150.degree. C. for 10
hours. After triethyl phosphite was distilled off under reduced
pressure, the residue was purified by column chromatography
(filler: silica gel, eluent: hexane/ethyl acetate=5/1) to obtain
2.5 g of a compound (6-f).
[0122] To 1.2 g of the compound (6-f) were added 10 ml of dimethyl
sulfoxide (manufactured by Wako Pure Chemical Industries, Ltd) and
1.08 g of a powder of potassium hydroxide (manufactured by Wako
Pure Chemical Industries, Ltd.), and during stirring at room
temperature, a solution of 2.4 g of the compound (6-C) in dimethyl
sulfoxide (6 ml) was added dropwise at room temperature over 1
hour. After completion of addition, the mixture was stirred at room
temperature for 5 hours. Fifty milliliter of water was added to the
reaction mixture, the mixture was extracted with 40 ml of hexane
three times, and the organic layer was dried over anhydrous
magnesium sulfate, and a solvent was distilled off under reduced
pressure. The residue was purified by column chromatography
(filler: silica gel, eluent: hexane) to obtain 540 mg of a compound
(6-g).
[0123] In 10 ml of tetrahydrofuran was dissolved 530 mg of the
compound (6-g), the solution was cooled to -78.degree. C., 0.65 ml
of n-butyllithium (1.6 M hexane solution) was added dropwise, and
the mixture was stirred at -78.degree. C. for 1 hour. The reaction
solution was stirred at 0.degree. C. for 30 minutes, and cooled to
-78.degree. C. again, and 440 mg of
2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane was added.
After the reaction solution was further stirred at room temperature
for 4 hours, 10 ml of water and, then, 50 ml of diethyl ether were
added. The organic layer was washed with 100 ml of water and, then,
30 ml of an aqueous saturated sodium chloride solution, and dried
over anhydrous magnesium sulfate, and a solvent was distilled off
under reduced pressure. Recrystallization from a mixed solvent of
methanol/acetone afforded 390 mg of a compound (6-h).
[0124] To 150 ml of 48% hydrobromic acid (manufactured by Wako Pure
Chemical Industries, Ltd.) were added 4.3 g of a compound (6-i)
(manufactured by Tokyo Chemical Industry Co., Ltd.) and 10 g of
bromine (manufactured by Wako Pure Chemical Industries, Ltd.), and
the mixture was stirred at 120.degree. C. for 3 hours. The mixture
was cooled to room temperature, and the precipitated solid was
filtered through a glass filter, and washed with 1000 ml of water
and 100 ml of acetone. The resulting solid was vacuum-dried at
60.degree. C. to obtain 6.72 g of a compound (6-j).
[0125] To 180 ml of ethanol was added 5.56 g of the compound (6-j),
13.2 g of NaBH.sub.4 (manufactured by Wako Pure Chemical
Industries, Ltd.) was added at 5.degree. C. under a nitrogen
atmosphere, and the mixture was stirred at room temperature for 2
days. After a solvent was distilled off, 500 ml of water was added,
and the solid was filtered, and washed with 1000 ml of water. The
resulting solid was dissolved in 200 ml of diethyl ether, washed
with 300 ml of water and dried over magnesium sulfate. A solvent
was distilled off to obtain 2.37 g of a compound (6-k).
[0126] To 80 ml of chloroform were added 2.37 g of the compound
(6-k) and 1.87 g of benzil (manufactured by Wako Pure Chemical
Industries, Ltd.), three droplets of methanesulfonic acid
(manufactured by Wako Pure Chemical Industries, Ltd.) was added
under a nitrogen atmosphere, and the mixture was heated to reflux
for 11 hours. The resulting solution was washed with an aqueous
sodium bicarbonate solution, and dried over magnesium sulfate. The
resulting solution was purified by column chromatography (filler:
silica gel, eluent: chloroform), and washed with methanol to obtain
3.72 g of a compound (6-1).
[0127] To 20 ml of tetrahydrofuran were added 1.0 g of the compound
(6-1) and 1.87 g of tributyl(2-thienyl)tin (manufactured by Tokyo
Chemical Industry Co., Ltd.), 32 mg of
bis(triphenylphosphine)palladium dichloride (manufactured by Tokyo
Chemical Industry Co., Ltd.) was further added under a nitrogen
atmosphere, and the mixture was heated to reflux for 5 hours. After
cooling to room temperature, 50 ml of methanol was added, and the
sedimented precipitate was filtered, and washed sequentially with
methanol, water and methanol. The resulting solid was purified by
column chromatography (filler: silica gel, eluent: dichloromethane)
to obtain 693 mg of a compound (6-m).
[0128] In 80 ml of dimethylformamide was dissolved 693 mg of the
compound (6-m), 550 mg of N-bromosuccinimide was added, and the
mixture was stirred at room temperature for 4 hours. To the
resulting solution was added 250 ml of water, and the sedimented
precipitate was filtered, and washed sequentially with water and
methanol. The resulting solid was purified by column chromatography
(filler: silica gel, eluent: dichloromethane), and washed with
methanol to obtain 900 mg of a compound (6-n).
[0129] In 15 ml of toluene were dissolved 91 mg of the compound
(6-n) and 99 mg of the compound (6-h). Four milliliter of water,
550 mg of potassium carbonate, 17 mg of tetrakis
(triphenylphosphine) palladium (0) and one droplet of Aliquat (R)
336 (manufactured by Aldrich) were added thereto, and the mixture
was stirred at 90.degree. C. for 7 hours under a nitrogen
atmosphere. Then, 20 mg of bromobenzene (manufactured by Tokyo
Chemical Industry Co., Ltd.) was added, and the mixture was stirred
at 90.degree. C. for 1 hour. Then, 40 mg of phenylboronic acid
(manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and
the mixture was stirred at 90.degree. C. for 1 hour. After
completion of stirring, the reaction mixture was cooled to room
temperature, and poured into 200 ml of methanol. The precipitated
solid was filtered, and washed sequentially with methanol, water,
and acetone. The resulting solid was dissolved in 100 ml of
chloroform, passed through a silica gel short column (eluent:
chloroform), concentrated, and re-precipitated into methanol to
obtain 35 mg of a compound [39]. A weight average molecular weight
was 12000, a number average molecular weight was 7500, and a
polymerization degree n was 14.0.
Synthesis Example 7
Synthesis of Compound [53]
[0130] The compound [53] was synthesized by a method showed in the
formula 7.
##STR00024##
Compound [53]
[0131] To 50 ml of tetrahydrofuran was added 2.0 g of
2,5-dibromo-3,4-dinitrothiophene (7-a) and 5.6 g of tributyl
(2-thienyl)tin, 0.21 g of bis(triphenylphosphine) palladium
dichloride was added under a nitrogen atmosphere, and the mixture
was heated to reflux for 5 hours. After cooling to room
temperature, 50 ml of hexane was added, and the sedimented
precipitate was filtered, and washed sequentially with hexane and
methanol. The resulting solid was purified by column chromatography
(filler: silica gel. eluent: dichloromethane), and washed with
methanol to obtain 2.0 g of a compound (7-b).
[0132] To 30 ml of ethanol were added 2.0 g of the compound (7-b)
and 2.8 g of a tin powder, 16 ml of 36% concentrated hydrochloric
acid was added thereto, and the mixture was heated to reflux at
80.degree. C. for 3 hours under a nitrogen atmosphere. After
cooling to room temperature, the reaction solution was added to 200
ml of a 10 wt % aqueous potassium hydroxide solution, and the
precipitate was filtered, and washed with water to obtain 0.89 g of
a compound (7-c).
[0133] To 15 ml of acetic acid were added 0.89 g of the compound
(7-c) and 0.67 g of benzil, and the mixture was stirred at
60.degree. C. for 5 hours under a nitrogen atmosphere. The
precipitated solid was filtered, and washed sequentially with
acetic acid, methanol, water and methanol to obtain 1.4 g of a
compound (7-d).
[0134] Then, 0.19 g of the compound (7-d) was dissolved in 15 ml of
chloroform, 3 ml of a solution of 0.15 g of N-bromosuccinimide
dissolved in DMF was added, and the mixture was stirred at room
temperature for 22 hours. One hundred milliliter of methanol was
added, and the produced solid was filtered, and washed sequentially
with methanol, water and methanol. The resulting solid was purified
by column chromatography (filler: silica gel, eluent,
dichloromethane), and washed with methanol to obtain 0.23 g of a
compound (7-e).
[0135] In 50 ml of toluene were dissolved 0.22 g of the compound
(7-e) and 0.20 g of the compound (3-a). Four milliliter of water,
1.0 g of potassium carbonate, 42 mg of tetrakis
(triphenylphosphine) palladium (0) and one droplet of Aliquat (R)
336 (manufactured by Aldrich) were added thereto, and the mixture
was stirred at 100.degree. C. for 3 hours under a nitrogen
atmosphere. Then, 40 mg of phenylboronic acid was added, and the
mixture was stirred at 100.degree. C. for 1 hour. To the resulting
solution was added 200 ml of methanol, and the produced solid was
filtered, and washed sequentially with methanol, water and acetone.
The resulting solid was dissolved in chloroform, passed through a
silica gel short column (eluent: chloroform), and concentrated to
dryness to obtain 80 mg of a compound (56). A weight average
molecular weight was 9264, a number average molecular weight was
5070, and a polymerization degree n was 11.0.
Synthesis Example 8
Synthesis of Organic Semiconductor OSC1
[0136] The organic semiconductor OSC1 was synthesized by a method
shown in the formula 8.
##STR00025##
[0137] A compound (8-a) (17 g) was cooled to 0.degree. C., and a
suspension obtained by adding 7.1 g of sodium hydride (60% oily) to
110 ml of tetrahydrofuran was added dropwise. The mixture was
stirred at 0.degree. C. for 20 minutes under a nitrogen atmosphere,
and 27 g of a compound (8-b) was added dropwise. Thereafter, a
temperature was raised to 90.degree. C., and the mixture was heated
to stir for 8 hours. To the reaction solution were added 100 ml of
water and 100 ml of dichloromethane, and the organic layer was
taken. The resulting organic layer was washed with 300 ml of an
aqueous saturated sodium chloride solution, and dried over
anhydrous sodium sulfate. The resulting solution was concentrated
with a rotary evaporator, and purified by column chromatography
(filler: silica gel, eluent: hexane/dichloromethane) to obtain 19.7
g of a compound (8-c).
[0138] In 90 ml of tetrahydrofuran was dissolved 12 g of the
compound (8-c), and the solution was cooled to -80.degree. C.
Thirty four milliliter of a butyllithium solution (1.6 M hexane
solution) was added dropwise thereto, and the mixture was stirred
for 6 hours. A temperature was raised to -30.degree. C., 10 g of
2-isopropoxy-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane was added
dropwise, and the mixture was stirred at room temperature for 18
hours. To the resulting solution were added 100 ml of water and 100
ml of hexane, and the organic layer was taken. The resulting
organic layer was washed with 300 ml of water, and dried over
anhydrous magnesium sulfate. A solvent was distilled off from the
resulting solution under reduced pressure using a rotary evaporator
to obtain 8.8 g of a compound (8-d).
[0139] To a mixed solution of 0.21 g of 4,4'-dibromostilbene, 0.69
g of the compound (8-d), 20 ml of toluene, 4 ml of ethanol and 5 ml
of a 2 M aqueous sodium carbonate solution was added 67 mg of
tetrakis(triphenylphosphine)palladium (0), and the mixture was
heated to stir at 100.degree. C. for 10 hours under a nitrogen
atmosphere. To the resulting solution were added 70 ml of
dichloromethane and 50 ml of water, and the organic layer was
taken. The resulting organic layer was washed with 150 ml of water,
and dried over anhydrous magnesium sulfate. The resulting solution
was concentrated with a rotary evaporator, and purified by column
chromatography (filler: silica gel, eluent: hexane/dichloromethane)
to obtain 80 mg of an organic semiconductor OSC1. The results of
.sup.1H-NMR analysis of the organic semiconductor OSC1 are
shown.
[0140] .sup.1H-NMR (CDCl.sub.3 (d=ppm)): 0.89-0.94 (t, 6H),
1.32-1.41 (m, 4H), 1.54-1.60 (t, 4H), 3.09-3.14 (t, 4H), 3.44-3.49
(t, 4H), 3.57-3.64 (m, 8H), 3.69-3.74 (t, 4H), 6.83-6.84 (d, 2H),
7.08 (s, 2H), 7.15-7.16 (d, 2H), 7.48-7.55 (dd, 8H)
Example 1
(1) Preparation of Semiconductor Coating Solution
[0141] To 30 ml of chloroform were added 1.5 mg of CNT
(manufactured by CNI, monolayer CNT, purity 95%, hereinafter
referred to as monolayer CNT) and 1.5 mg of the compound [21], and
the mixture was ultrasound-stirred at an output of 250 W for 30
minutes using an ultrasound homogenizer (VCX-500 manufactured by
TOKYO TIKAKAI CO., LTD.) while ice-cooling. At the timepoint at
which ultrasound irradiation was performed for 30 minutes,
irradiation was stopped once, 1.5 mg of the compound [21] was
additionally added and, further, ultrasound was irradiated for one
minute, thereby, a CNT composite pre-dispersion A (CNT
concentration relative to a solvent 0.05 g/l) was obtained.
[0142] In order to investigate whether the compound [21] was
attached to CNT in the CNT composite pre-dispersion A or not, 5 ml
of the CNT composite pre-dispersion A was filtered using a membrane
filter to trap CNT on the filter. The trapped CNT was quickly
transferred onto a silicon wafer before a solvent was dried, to
obtain dried CNT. When this CNT was subjected to elementary
analysis using X-ray photoelectron spectroscopy (XPS), a sulfur
element contained in the compound [21] was detected. Therefore, it
was confirmed that the compound [21] was attached to CNT in the CNT
composite pre-dispersion A.
[0143] Then, a semiconductor coating solution for forming a
semiconductor layer 4 was prepared. The CNT composite
pre-dispersion A was filtered using a membrane filter (pore
diameter 10 .mu.m, diameter 25 mm, Omnipore Membrane manufactured
by Millipore) to remove CNT having a length of 10 .mu.m or more.
The resulting filtrate was designated as CNT composite dispersion
A. The CNT composite dispersion A (0.2 ml) and 0.8 ml of
1,2,3,4-tetrahydronaphthalene were mixed, 5 mg of the OSC1 as an
organic semiconductor was added to prepare a semiconductor coating
solution. Thereupon, concentrations were adjusted so that an OSC1
concentration became 5 g/l, and a concentration of the CNT
composite became 0.2 part by weight relative to 100 parts by weight
of OSC1.
(2) Preparation of Polymer Solution for Gate Insulating Layer
[0144] In 203.36 g of propylene glycol monobutyl ether (boiling
point 170.degree. C.) were dissolved 61.29 g (0.45 mol) of
methyltrimethoxysilane, 12.31 g (0.05 mol) of
.beta.-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 99.15 g (0.5
mol) of phenyltrimethoxysilane, and 54.90 g of water and 0.864 g of
phosphoric acid were added thereto while stirring. The resulting
solution was heated at a bath temperature of 105.degree. C. for 2
hours, and an internal temperature was raised to 90.degree. C. to
distill off a component containing mainly methanol as a byproduct.
Then this was heated at a bath temperature of 130.degree. C. for
2.0 hours, an internal temperature was raised to 118.degree. C. to
distill off a component containing water mainly, and this was
cooled to room temperature to obtain a polymer solution A having a
solid matter concentration of 26.0% by weight.
[0145] Fifty gram of the resulting polymer solution A was weighed,
this was mixed with 16.6 g of propylene glycol monobutyl ether
(boiling point 170.degree. C.), and the mixture was stirred at room
temperature for 2 hours to obtain a polymer solution B (solid
matter concentration 19.5% by weight).
(3) Preparation of FET
[0146] FET shown in FIG. 1 was manufactured. Chromium of 5 nm and
gold of 50 nm were vacuum-deposited on a grass substrate 1 (film
thickness 0.7 mm) through a mask by a resistance heating method, to
form a gate electrode 2. Then, the polymer solution B prepared by
the method described in the (2) was spin-coated (2000 rpm.times.30
seconds) on the grass substrate on which the gate electrode had
been formed, and this was heat-treated at 200.degree. C. for 1 hour
under a nitrogen stream, thereby, a gate insulating layer 3 having
a film thickness of 600 nm was formed. Then, gold was
vacuum-deposited through a mask by a resistance heating method, so
that a film thickness became 50 nm, to form a source electrode 5
and a drain electrode 6.
[0147] A width of these both electrodes (channel width) was 0.1 cm,
and an interval between both electrodes (channel length) was 100
.mu.m. The semiconductor coating solution (1 .mu.L) prepared by the
method described in the (1) was added dropwise to a substrate on
which electrodes had been formed, and this was air-dried at
30.degree. C. for 10 minutes, and heat-treated at 150.degree. C.
for 30 minutes on a hot plate under a nitrogen stream to obtain
FET.
[0148] Then, current between source and drain (Id)-voltage between
source and drain (Vsd) property when a gate voltage (Vg) of the FET
was changed, was measured. For measurement, a semiconductor
property assessment system, Model 4200-SCS (manufactured by
Keithley Instruments Inc.) was used, and the property was measured
in the atmospheric air. When mobility of a linear region was
obtained from change in a value of Id at Vsd=-5 V when Vg was
changed as Vg=+30.about.-30 V, it was 0.48 cm.sup.2/Vsec. In
addition, when an on off ratio was obtained from a ratio of maximum
and minimum of Id thereupon, it was 7.5.times.10.sup.4. Further,
hysteresis was obtained from an absolute value of a gate voltage
difference between forward and reverse |Vg.sup.1-Vg.sup.2| at
Id=10.sup.-8, it was 11 V and, when a threshold voltage was
obtained from an intersection between an extension line of a linear
part and a Vg axis in an Id-Vg graph, it was 10 V.
Examples 2 to 9
[0149] According to the same manner as in Example 1 except that the
conjugated polymer and the organic semiconductor for forming the
CNT composite were changed as shown in Table 1, a CNT composite
dispersion was prepared. When this was subjected to elementary
analysis using XPS, it was confirmed that the conjugated polymer
was attached to CNT. Then, FET was manufactured using the CNT
composite dispersion according to the same manner as in Example 1,
and property was measured. The results are shown in Table 1.
Comparative Example 1
[0150] According to the same manner as in Example 1 except that
poly-3-hexylthiophene (manufactured by Aldrich, Regioregular,
number average molecular weight (Mn): 13000, hereinafter referred
to as P3HT) was used as the conjugated polymer for forming the CNT
composite, a CNT composite dispersion E was prepared. When this was
subjected to elementary analysis using XPS, it was confirmed that
P3HT was attached to CNT. Then, according to the same manner as in
Example 1 except that the CNT composite dispersion E was used in
place of the CNT composite dispersion A, FET was manufactured, and
property was measured. When Vg was changed as Vg=+30.about.-30 V,
mobility was 0.37 cm.sup.2/Vsec, and an on off ratio was
4.30.times.10.sup.3. In addition, hysteresis was 20 V, and a
threshold voltage was 11 V.
Comparative Example 2
[0151] According to the same manner as in Example 1 except that
poly-3-octylthiophene (manufactured by Aldrich, Regioregular,
number average molecular weight (Mn): 10000, hereinafter referred
to as 23OT) was used as the conjugated polymer for forming the CNT
composite, a CNT composite dispersion F was prepared. When this was
subjected to elementary analysis using XPS, it was confirmed that
P3OT was attached was CNT. Then, according to the same manner as in
Example 1 except that the CNT composite dispersion F was used in
place of the CNT composite dispersion A, FET was manufactured, and
property was measured. When Vg was changed as Vg=+30.about.-30 V,
mobility was 7.3.times.10.sup.-2 cm.sup.2/Vsec, and an on off ratio
was 1.01.times.10.sup.4. In addition, hysteresis was 24 V, and a
threshold voltage was 13 V.
Example 10
[0152] The CNT composite dispersion G (0.2 ml) prepared in Example
7, 0.3 ml of 1,2-dichrolomenzene and 0.5 ml of
tetrahydronaphthalene were mixed to prepare a semiconductor coating
solution I. According to the same manner as in (3) of Example 1
except that the semiconductor coating solution I was used as a
solution for forming the semiconductor layer 4, FET was
manufactured, and property was measured. The results are shown
Table 1.
Example 11
[0153] On a semiconductor layer 4 of FET manufactured as in Example
4 was dropping-cast 10 .mu.l of a 20 wt % butanol solution of an
acryl resin SPCR-6.times.(manufactured by SHOWA DENKO K.K.), to
form a second insulating layer. Subsequently, the layer was
air-dried at 30.degree. C. for 5 minutes, and heat-treated at
140.degree. C. for 30 minutes on a hot plate under a nitrogen
stream to manufacture FET having a second insulating layer, and
property was measured. The results are shown in Table 1.
Example 12
[0154] According to the same manner as in Example 11 except that
the compound [33] was used as the conjugated polymer for forming
the CNT composite, FET having a second insulating layer was
manufactured, and property was measured. The results are shown in
Table 1.
Example 13
[0155] According to the same manner as in Example 11 except that
the compound [39] was used as the conjugated polymer for forming
the CNT composite, FET having a second insulating layer was
manufactured, and property was measured. The results are shown in
Table 1.
Example 14
[0156] On a semiconductor layer 4 of FET manufactured as in Example
7 was dropping-cast 10 .mu.L of a 5 wt % methyl ethyl ketone
solution of poly (methyl methacrylate) (manufactured by Aldrich,
weight average molecular weight (Mw): 350000, hereinafter referred
to as PMMA), to form a second insulating layer. Subsequently, the
layer was air-dried at 30.degree. C. for 5 minutes, and
heat-treated at 120.degree. C. for 30 minutes on a hot plate under
a nitrogen stream to manufacture FET having a second insulating
layer, and property was measured. The results are shown in Table
1.
Example 15
[0157] According to the same manner as in Example 14 except that a
second insulating layer was formed using the polymer solution B
prepared in (2) of Example 1, FET having a second insulating layer
was manufactured, and property was measured. The results are shown
in Table 1.
Example 16
[0158] According to the same manner as in Example 14 except that a
second insulating layer was formed using a 5 wt % butanol solution
of polyvinylphenol (manufactured by Aldrich, weight average
molecular weight (Mw): 20000, hereinafter referred to as PVP), FET
having a second insulating layer was manufactured, and property was
measured. The results are shown in Table 1.
Example 17
[0159] According to the same manner as in Example 11 except that
the semiconductor layer 4 was formed as in Example 10, FET having a
second insulating layer was manufactured, and property was
measured. The results are shown in Table 1.
Example 18
[0160] According to the same manner as in Example 12 except that a
second insulating layer was formed using a solution obtained by
adding 3-aminopropyltriethoxysilane (manufactured by Aldrich,
hereinafter referred to as APS) to the 20 wt % butanol solution of
SPCR-6.times. at an amount of 5 parts by weight relative to 100
parts by weight of SPCR-6.times., organic FET was manufactured, and
property was measured. The results are shown in Table 1.
Example 19
[0161] According to the same manner as in Example 18 except that
the compound [39] was used as the conjugated polymer for forming
the CNT composite, organic FET was manufactured, and property was
measured. The results are shown in Table 1.
TABLE-US-00001 TABLE 1 Second Threshold Conjugated CNT composite
Organic insulating Mobility On off Hysteresis voltage polymer
dispersion semiconductor layer (cm.sup.2/Vs) ratio (V) (V) Example
1 Compound 21 CNT composite OSC 1 -- 0.48 7.5 .times. 10.sup.4 11
10 dispersion A Example 2 Compound 22 CNT composite OSC 1 -- 0.34
4.1 .times. 10.sup.4 13 13 dispersion B Example 3 Compound 23 CNT
composite OSC 1 -- 0.47 1.1 .times. 10.sup.5 10 14 dispersion C
Example 4 Compound 24 CNT composite OSC 1 -- 0.51 5.8 .times.
10.sup.4 12 10 dispersion D Example 5 Compound 24 CNT composite OSC
2 -- 0.18 4.6 .times. 10.sup.4 10 11 dispersion D Example 6
Compound 24 CNT composite OSC 3 -- 0.15 3.8 .times. 10.sup.4 11 9.5
dispersion D Example 7 Compound 33 CNT composite OSC 1 -- 0.38 1.0
.times. 10.sup.5 11 11 dispersion G Example 8 Compound 39 CNT
composite OSC 1 -- 0.17 3.8 .times. 10.sup.4 11 13 dispersion H
Example 9 Compound 53 CNT composite OSC 1 -- 0.31 7.5 .times.
10.sup.4 12 13 dispersion J Example 10 Compound 33 CNT composite --
-- 0.26 4.2 .times. 10.sup.5 10 10 dispersion I Example 11 Compound
24 CNT composite OSC 1 SPCR-6X 0.19 4.2 .times. 10.sup.5 3.8 1.8
dispersion D Example 12 Compound 33 CNT composite OSC 1 SPCR-6X
0.33 2.2 .times. 10.sup.6 2.9 1.5 dispersion G Example 13 Compound
39 CNT composite OSC 1 SPCR-6X 0.13 4.4 .times. 10.sup.5 4.5 2.1
dispersion H Example 14 Compound 33 CNT composite OSC 1 PMMA 0.25
8.9 .times. 10.sup.5 3.1 2.8 dispersion G Example 15 Compound 33
CNT composite OSC 1 PCC 0.21 3.1 .times. 10.sup.6 5.5 5.7
dispersion G Example 16 Compound 33 CNT composite OSC 1 PVP 25 5.7
.times. 10.sup.5 6.7 4.5 dispersion G Example 17 Compound 33 CNT
composite -- SPCR-6X 0.34 5.8 .times. 10.sup.6 3.3 1.2 dispersion G
Example 18 Compound 33 CNT composite OSC 1 SPCR-6X APS 0.5 1.0
.times. 10.sup.5 4.3 0.8 dispersion G Example 19 Compound 39 CNT
composite OSC 1 SPCR-6X APS 0.14 7.3 .times. 10.sup.5 3.9 1.3
dispersion H Comparative P3HT CNT composite OSC 1 -- 0.37 4.3
.times. 10.sup.3 20 11 Example 1 dispersion E Comparative P3OT CNT
composite OSC 1 -- 0.073 1.0 .times. 10.sup.4 24 13 Example 2
dispersion F OSC1: Organic semiconductor synthesized in Synthesis
Example 8 OSC2:
Poly(2,5-bis(2-thienyl)-3,6-dipentadecylthieno[3,2-b]thiophene)
OSC3: Poly(5,5'-bis(4-octylthiazol-2-yl)-2,2'-bithiophene)
INDUSTRIAL APPLICABILITY
[0162] The CNT composite of the present invention is suitably used
in various devices such as a field-effect transistor, a
photovoltaic power element, and a switching element.
EXPLANATION OF SYMBOLS
[0163] 1 Substrate [0164] 2 Gate electrode [0165] 3 Gate insulating
layer [0166] 4 Semiconductor layer [0167] 5 Source electrode [0168]
6 Drain electrode
* * * * *